Using old wiring for new model alarm Options

[ravinaziankid]

Hey, I just bought this celica, it already has an alarm setup but the seller didn't give me the remote for it, so I have no way of using it unless I pick up the remotes and program it. The alarm in the car now is a prestige 996 model, but the thing is, it costs 70 each remote and another for the LCD one. I see the newer model 997 selling for 140 brand new. I just want to know if I can just unplug the harness from the old alarm and hook it up to the new one with no probs. I'm asking because this will save me time and hassle of doing everything over again.